queue: more queue optimizations

Split gst_queue_locked_enqueue() into variant for buffer and event to get rid of
the if() and make the code more readable (constant boolean parameters are never
nice). Removes the if (item) checks as we dereference the pointer before anyway.

Also apply the same idea of reusing the previous knowledge in
gst_queue_locked_dequeue to remove more type checks.

plugins/elements/gstqueue.c

@@ -656,9 +656,8 @@ gst_queue_locked_flush (GstQueue * queue)
 
 /* enqueue an item an update the level stats, with QUEUE_LOCK */
 static inline void
-gst_queue_locked_enqueue (GstQueue * queue, gpointer item, gboolean isbuffer)
+gst_queue_locked_enqueue_buffer (GstQueue * queue, gpointer item)
 {
-  if (isbuffer) {
   GstBuffer *buffer = GST_BUFFER_CAST (item);
 
   /* add buffer to the statistics */
@@ -674,7 +673,14 @@ gst_queue_locked_enqueue (GstQueue * queue, gpointer item, gboolean isbuffer)
    * See #482147 */
   /*     if (queue->cur_level.buffers == 1) */
   /*       apply_buffer (queue, buffer, &queue->src_segment, FALSE); */
-  } else {
+
+  g_queue_push_tail (queue->queue, item);
+  GST_QUEUE_SIGNAL_ADD (queue);
+}
+
+static inline void
+gst_queue_locked_enqueue_event (GstQueue * queue, gpointer item)
+{
   GstEvent *event = GST_EVENT_CAST (item);
 
   switch (GST_EVENT_TYPE (event)) {
@@ -695,16 +701,14 @@ gst_queue_locked_enqueue (GstQueue * queue, gpointer item, gboolean isbuffer)
     default:
       break;
   }
-  }
 
-  if (item)
   g_queue_push_tail (queue->queue, item);
   GST_QUEUE_SIGNAL_ADD (queue);
 }
 
 /* dequeue an item from the queue and update level stats, with QUEUE_LOCK */
 static GstMiniObject *
-gst_queue_locked_dequeue (GstQueue * queue)
+gst_queue_locked_dequeue (GstQueue * queue, gboolean * is_buffer)
 {
   GstMiniObject *item;
 
@@ -725,6 +729,8 @@ gst_queue_locked_dequeue (GstQueue * queue)
     /* if the queue is empty now, update the other side */
     if (queue->cur_level.buffers == 0)
       queue->cur_level.time = 0;
+
+    *is_buffer = TRUE;
   } else if (GST_IS_EVENT (item)) {
     GstEvent *event = GST_EVENT_CAST (item);
 
@@ -742,6 +748,8 @@ gst_queue_locked_dequeue (GstQueue * queue)
       default:
         break;
     }
+
+    *is_buffer = FALSE;
   } else {
     g_warning
         ("Unexpected item %p dequeued from queue %s (refcounting problem?)",
@@ -817,7 +825,7 @@ gst_queue_handle_sink_event (GstPad * pad, GstEvent * event)
         /* refuse more events on EOS */
         if (queue->eos)
           goto out_eos;
-        gst_queue_locked_enqueue (queue, event, FALSE);
+        gst_queue_locked_enqueue_event (queue, event);
         GST_QUEUE_MUTEX_UNLOCK (queue);
       } else {
         /* non-serialized events are passed upstream. */
@@ -880,8 +888,9 @@ gst_queue_leak_downstream (GstQueue * queue)
   /* for as long as the queue is filled, dequeue an item and discard it */
   while (gst_queue_is_filled (queue)) {
     GstMiniObject *leak;
+    gboolean is_buffer;
 
-    leak = gst_queue_locked_dequeue (queue);
+    leak = gst_queue_locked_dequeue (queue, &is_buffer);
     /* there is nothing to dequeue and the queue is still filled.. This should
      * not happen */
     g_assert (leak != NULL);
@@ -981,7 +990,7 @@ gst_queue_chain (GstPad * pad, GstBuffer * buffer)
   }
 
   /* put buffer in queue now */
-  gst_queue_locked_enqueue (queue, buffer, TRUE);
+  gst_queue_locked_enqueue_buffer (queue, buffer);
   GST_QUEUE_MUTEX_UNLOCK (queue);
 
   return GST_FLOW_OK;
@@ -1034,13 +1043,14 @@ gst_queue_push_one (GstQueue * queue)
 {
   GstFlowReturn result = GST_FLOW_OK;
   GstMiniObject *data;
+  gboolean is_buffer;
 
-  data = gst_queue_locked_dequeue (queue);
+  data = gst_queue_locked_dequeue (queue, &is_buffer);
   if (data == NULL)
     goto no_item;
 
 next:
-  if (GST_IS_BUFFER (data)) {
+  if (is_buffer) {
     GstBuffer *buffer;
     GstCaps *caps;
 
@@ -1081,12 +1091,12 @@ next:
        * can push again, which is EOS or NEWSEGMENT. If there is nothing in the
        * queue we can push, we set a flag to make the sinkpad refuse more
        * buffers with an UNEXPECTED return value. */
-      while ((data = gst_queue_locked_dequeue (queue))) {
-        if (GST_IS_BUFFER (data)) {
+      while ((data = gst_queue_locked_dequeue (queue, &is_buffer))) {
+        if (is_buffer) {
           GST_CAT_LOG_OBJECT (queue_dataflow, queue,
               "dropping UNEXPECTED buffer %p", data);
           gst_buffer_unref (GST_BUFFER_CAST (data));
-        } else if (GST_IS_EVENT (data)) {
+        } else {
           GstEvent *event = GST_EVENT_CAST (data);
           GstEventType type = GST_EVENT_TYPE (event);
 
@@ -1109,7 +1119,7 @@ next:
       queue->unexpected = TRUE;
       result = GST_FLOW_OK;
     }
-  } else if (GST_IS_EVENT (data)) {
+  } else {
     GstEvent *event = GST_EVENT_CAST (data);
     GstEventType type = GST_EVENT_TYPE (event);